1. Field of the Invention
This invention relates generally to flow control apparatus and particularly to a device having a variable, pressure-responsive restriction for maintaining a substantially constant flow rate above a predetermined supply pressure irrespective of the pressure drop across the device and the direction of flow in the conduit in which the device is installed.
2. History of the Prior Art
Various kinds of fluid flow devices presently exist for maintaining a predetermined volumetric flow rate irrespective of variations in the supply pressure. Such devices are typically found in water fountains, faucets and like installations and are presently assuming increasing importance as greater consideration is given the conservation of water.
Certain flow control devices of the prior art employ one or more elastomeric members deformable in some fashion by the applied fluid pressure to vary the flow restricting cross-sectional area of a channel, orifice or the like in accordance with the pressure but such devices have several drawbacks.
For example, in almost all instances these devices are directional, that is, they control the flow rate in only one direction of fluid flow and therefore must be installed with the correct orientation in order to function properly.
Further, short of complete disassembly of the conduit means in which the control device is installed, there is no way of readily ascertaining whether the elastomeric member has deteriorated and requires replacement, or whether the flow control device is in place at all.